Re: shared_buffers/effective_cache_size on 96GB server - Mailing list pgsql-performance

From Bruce Momjian
Subject Re: shared_buffers/effective_cache_size on 96GB server
Date
Msg-id 20121010161012.GE11892@momjian.us
Whole thread Raw
In response to Re: shared_buffers/effective_cache_size on 96GB server  (Julien Cigar <jcigar@ulb.ac.be>)
Responses Re: shared_buffers/effective_cache_size on 96GB server  (Claudio Freire <klaussfreire@gmail.com>)
List pgsql-performance
On Wed, Oct 10, 2012 at 10:11:30AM +0200, Julien Cigar wrote:
> On 10/10/2012 09:12, Strahinja Kustudić wrote:
> >Hi everyone,
>
> Hello,
>
> >
> >I have a Postgresql 9.1 dedicated server with 16 cores, 96GB RAM
> >and RAID10 15K SCSI drives which is runing Centos 6.2 x64. This
> >server is mainly used for inserting/updating large amounts of data
> >via copy/insert/update commands, and seldom for running select
> >queries.
> >
> >Here are the relevant configuration parameters I changed:
> >
> >shared_buffers = 10GB
>
> Generally going over 4GB for shared_buffers doesn't help.. some of
> the overhead of bgwriter and checkpoints is more or less linear in
> the size of shared_buffers ..
>
> >effective_cache_size = 90GB
>
> effective_cache_size should be ~75% of the RAM (if it's a dedicated server)

Why guess?  Use 'free' to tell you the kernel cache size:

    http://momjian.us/main/blogs/pgblog/2012.html#May_4_2012

--
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + It's impossible for everything to be true. +


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